Speed governor for injection internal combustion engines



Dot; 1], 1938. v SCHWEIQZER 2,132,445

SPEED GOVERNOR FORYINJECTION INTERNAL COMBUSTION ENGINES Filed Jan. 11. 1934 2 Sheets-Sheet 1 Oct. 11, 1938 A. scHwElzER SPEED GOVERNOR FOR INJECTION. INTERNAL COMBUSTION ENGINES- 2 Sheets-Sheet 2 Filed Jan. 11. 1954 Ill,

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w i w I YIII'IIII/ Patented Oct. 11, 1938 1 SPEED GOVERNOR FOR. INJECTION "m'rEn- NAL COMBUSTION ENGINES Alfred Schweizer, Stuttgart, Germany, assignor to Robert Bosch Gesellschaft mit beschrankter Haftung, Stuttgart, Germany Application January 11, 1934, Serial No. 706,298

In Germany October -7, 1933 14 Claims.

The present invention relates to speed governors for injection internal combustion engines.

In apparatus for governing the speed of an injection internal combustion engine, it is known 5 to employ governing means which are operated by the vacuum which exists in the suction pipe of the engine and varies with its speed instead of centrifugal governors. To obtain the forces which efiect the control, either the static vacuum, or in other cases even a kinetic vacuum, was utilized in theseknown arrangements. The static vacuum in the suction pipe is principally produced by throttle members such as throttle-valves built into the suction pipe, and is dependent, assuming the throttling remains the same, on the speed of the engine. The voluntary alteration of the speed is produced by altering the position of the throttle-valve. Variations in theengine speed manifest themselves, more par- 20 ticularly at low speeds, as when running light,

that is, when the throttle member almost entirely closes the cross sectioncf the suction pipe, in great variations in the vacuum. At high speeds, i. a, when the throttle-valve fully opens the passage, the influence on' the vacuum of variations in speed is only very slight, in view of the large cross section of the suction pipe. The described mode of using the static vacuum in the suction pipe for controlling the speed of the engine therefore proves very good for controlling the speed when the engine is running light. With increasing speed, however, the sensitiveness of a governor based on this mode of governing becomes less and less, and at the highest speeds even insuflicient in manycases.

The second known way of employing the pressure conditions in the suction pipe for governing the speed is to create difi'erences in current by providing contractions in the cross section of the suction pipe in the manner of a Venturi tube, these difierences varying with the current speed of the air drawn in, which depends on the speed of the engine. The voluntary variation in speed can here be effected in various way, for instance, by altering the resistance or counter-force of the controlling device itself. The force for adjusting or operating the controlling arrangement is ob-" tained by utilizing the difference between the kinetic vacuum atthe narrowest cross section and the free. atmosphere, or "between the said kinetic vacuum and that :at a point of. greater cross section. Such a governingyarrangement requires a certain current speed of ,the air to be generally effective. At such low speeds as one endeavours to obtain nowad ys, which even do actually occur with injection internal combustion engines for vehicles when running light, this minimum value is hardly attained. A governing arrangement based on this mode of governing thus does not, or only very imperfectly meets requirements at such speeds. It is only at fairly high speeds that this mode of governing can be successfully employed, and it attains its best effi'ciency at the highest speeds.

By the present invention a governing arrangement is provided which works at all speeds with equal sensitiveness. This is attained by combining the two modes of governing hitherto only used separately, that is, by the simultaneous production of a kinetic vacuum and a static vacuum in the suction. pipe of the engine. At the lower speeds, mainly, the static vacuum will first act on the governing member, but as the speed increases will become' increasingly less effective, whilst the effectiveness of the kinetic pressure becomes increasingly greater and finally entirely replaces the former. By this means the result is attained that the sensitiveness of the new governing ar-- rangement remains as uniforin as possible over the whole range of speeds.

An example of construction of the invention is shown diagrammatically in the accompanying drawings, in which:-

- Figure 1 shows the invention in combination with an injection pump on a four-cylinder engine.

Figure 2 is a section through those parts of the injection pump and the suction pipe of the engine whose description is necessary for understanding the invention.

Figure 3' shows a further form of construction of the suction pipe.

In the form of the invention shown in Figs. 1, and 2, the base part I of the engine supports four cylinders 2 and an injection pump 3, which is driven from the engine shaft through gearing 4,

' 5. Fuel is supplied to the injection pump from a container (not shown) through a ipe 6. Four delivery pipes I lead from the injection pump to the heads of the cylinders 2. The necessary air is drawn in through the common suction-pipe 8. In the suction pipe a throttle-valve 9 is provided, which is operated by means of a lever 9a connected to it from a pedal lever 9b. Behind the throttle-valve 9, looked at in the direction of the suction current, a Venturi tube-like contraction .I0 is provided in the suction-pipe 8 and at its narrowest point a second Venturi tube Illa is arranged. A vacuum pipe l5 leads from the nar- .,rowest point ofthe Venturi tube Illa to the gov- -.erning part 3a of the pump 3. The part 3a con- 86 tains a chamber in which a piston 24 is longitudinally displaceable. The vacuum supplied to the part of the chamber situated to the light of the piston 24 tends to move the piston 24 to the right, in opposition to the action of a return spring'2l. The piston 24 is fastened by a nut 26 to the end of a toothed rack-bar 23 which projects from the pump into the controlling chamber. The part of the chamber 3a situated to theleft of the piston 24 is connected to the atmosphere by an opening 25. g

The governing of the injected fuel is effected by moving the toothed rack bar 23. If the rack bar is moved to the right, the effective quantity delivered by all the pumps is uniformly reduced. By moving the rack bar to the left, the injection quantity delivered by all the pumps is increased. The toothed bar 23 meshes with pinions 22. Each of the pump'pistons I6 driven by a cam-shaft i8 coupled to the engine is coupled in such a way with one such pinion that it must follow the rotary movements of the pinion, without this latter having to share in the strokes of the piston. By the simultaneous and equal rotation of the pistons, the position of the oblique controlling edge 2| provided on each of them is so adjusted relative to' the suction and return flow passage 20, that the effective stroke of the pump pistons ceases earlier or later according to the adjusted position of the'oblique controlling edges, and the fuel compressed by the piston in the remaining part of each pumping pressure stroke flows back through the passage 20 into the suction chamber I9 in the pump casing} connected to the fuel supply pipe 6.

The mode of action of the new governing apparatus shown in Figs. 1 and 2 is as follows:-

The vacuum obtaining in the suction pipeboth the static vacuum produced essentially by the throttle-valve 9, as well as the dynamic vacuum produced by the Venturi tubes l0 and Ilia, is led through the conducting member I5 to the governing chamber. The running speed or R. P. M. of the engine and thus the vacuum in the suction pipe 8 are adjusted at: ,flrst to a certain value. If now that speed rises, for example, owing to the engine being relieved of load, whilst the adjustment of the throttle-valve remains the same, the static vacuum in the suction pipe and also the dynamic .vacuum at the narrowest part of the Venturi tube I0 increases beyond the vacuum previously prevailing. The increased vacuum then pulls the piston, together with the controlling rod 23, to the right, so that the pinions 22 rotate in such a way that the quantity of fuel injected at each pumping stroke is reduced. The speed will thereupon sink, which results in a corresponding renewed drop in the vacuum in the suction pipe. The piston 24 again assumes the position corresponding to this vacuum. A certain engine speed corresponds therefore-assuming the position of the throttle- .va'lve remains the sameto a definite position of the piston 24. Thevoluntary variation of the speed is effected by adjusting the throttle valve 9.

Instead of the throttle 9 and the Venturi tube I0 being arranged in succession, as in the example described, it would also be possible to arrange the throttle-valve behind the Venturi tube, looked at in the direction of current, which of course makes a wider supply pipe necessary. Figure 3 shows this case. Two pipes I5a and I5b branch ofl from the suction pipe. (lia) leads from the vacuum chamber behind One of them the throttle-valve 9 to a three-way cook 28. The pipe l5b leads from the Venturi tube Ilia, to this three-way cock, which is adjusted with the valve 9 by the lever 90. from the foot-lever 917 by means of a rocking lever 28a. The position of these levers and the position of the V-shaped passage or port 29 in the cook 28 are so selected that with the throttle-valve quite closed, that is, in the position when the engine is running light, only the pipe I5a is connected with the pipe I5 and thus with the controlling chamber in the casing So as shown in Fig. 3. When the valve 9 is fully open, only the Venturi tube Illa is incommunication with the governing device through the connecting members I51) and I5. In the intermediate positions both branches I51; and i512 are connected with the pipe I5. The arrangement described is adopted in order to avoid, as would be the case with an open three-way pipe, the action of the Venturi tube being weakened by connecting the pipe I51), I5 with a place having a substantially lower kinetic vacuum, i. e.,-through the connecting member l5a.

In the arrangement illustrated the vacuum operates upon a control member which consists of the piston 24, but obviously a diaphragm, an

oscillatable vane or other displaceable member could be employed.

I declare that what I claim is:

1. The combination with a fuel injection internal combustion engine having an air suction intake pipe and a fuel injection pump driven by said engine, of speed control means for said engine comprising means in said intake. pipe cooperating with the engine piston to create a static ing degrees of negative pressures of. said vacua to v correspondingly reduce the rate of fuel delivery of said pump.

2. The combination with a fuel injection internal combustion engine having an air suction intake pipe and a fuel injection pump driven by said engine, of speed control means for said engine comprising a throttle valve and a Venturi throat spaced apart within said air intake pipe and cooperating with the engine piston to create a static and a dynamic vacuum in said air intake pipe of changing degrees of negative pressures as said throttle valve is moved from the idle running position to full open position, a displaceable control member, a casing for said control member open to atmosphere on one side of said control member, conduit means connecting said casing on the opposite side of said control memberwith said air intake pipe at a point exposing said control member on its said opposite side to the influence of both said static and dynamic vacua whereby said control member is displaced in one direction to varying extents dependent on said changing degrees of negative pressures in said intake pipe as said throttle valve is moved toward full open position, and means connecting said control member with said fuel injection pump within said intake pipe and operating respectively upon reciprocation of the engine piston to produce a static and a dynamic vacuum in said pipe of varying degree of negative pressures over the range of speeds of said engine, a control member displaceable in one drection under the influence of negative'pressure thereon, a casing for said control member open to atmosphere on one side of said member, a duct connecting said restriction with said casing on the opposite side'ofsaid control member to effect displacementof said member to varying extents dependent on the degree of negative pressure effective on said control member, and means operated by said displacement of said control member to reduce. the rate of fuel delivery of said pump. v

4. The combination with a fuel injection internal combustion engine having an airsuction intake pipe and a fuel injection pump driven by said engine, of speed control means for said engine comprising a choke tube in .said'intake pipe. a throttle valve in said intake pipe on the engine side of said choke tube, a control member displaceable in one direction under the influence of negative pressures thereon, a casing for said control member open to atmosphere on one side of sad member, conduit means connecting said choke tube and said intake pipe on the engine side of said throttle valve with said casing on the opposite side of said control member to effect displacement of said member to varying extents dependent on the degrees of negative pressure eflective on said control member, and means operated by said displacement of said control member to reduce the rate of fuel delivery of said pump in accordance with the extent of said displacement of said control member.

5. The combination with a fuel injection internal combustion engine. and speed control means therefor as defined in claim 4 and further characterized by valve means operatively associated with said conduit means to alternately or simultaneously connect said choke tube and said air intake pipe on the engine side of said throttle valve with said casing of said control member.

6. The combination with a fuel injection internal combustion engine and speed control means therefor as deflned in claim 4 and further characterized by a valve member in said conduit means connected with said throttle valve for operation by said throttle valve whereby in the position of saidthrottle valve corresponding to idle running of said engine said valve member connects said air intake pipe on the engine side of said throttle .valve with said casing of said 'control'member without connecting said choke tube with said casing, movement of said throttle valve to full open position operates said valve member to connect said choke tubewith said choke tube and said air intake pipe on the engine side of said throttle valve simultaneously with said casing of said control member.

7. The combination with a fuel injection internal combustion engine having an air suction intake pipe and a fuel injection pump driven by said engine, of speed control means for said engine comprising a throttle valve and a Venturi tube on the engine side of said valve within said air intake pipe, a piston, a cylinder for said piston open to atmosphere on one side of said piston and connected on the otherside of said piston to said Venturi tube to effect displacement of said piston to varying extents dependent on the degree of negative pressure developed in said air intake pipe, and means operated by said displacement of said piston to reduce the rate offuel delivery of said pump.

8. The combination with a fuel injection internal combustion engine having an air suctionintake pipe and liquid fuel-supplying means, of speed control means for said engine comprising means in said intake pipe cooperating with the engine piston to create a-static and a dynamic vacuum in said pipe of changing degrees of negative pressures over the range of speeds of said thereof, means exposing one face of said control member to said static and dynamic vacua in said intake pipe to effect said displacement of said control member to varying extents in accordance with said changing degrees of negative pressures of said vacua, and means operated by said dis- 4 placement of said control member to correspondingly reduce the rate of fuel delivery of said fuelsupplying means. a

9. The combination with a fuel injection internal combustion engine having an air suction intake pipe and a'liquid fuel-supplying means, of speed control means for said engine comprising separate means in said intake pipe cooperating with, the engine piston to create a staticand a dynamic vacuum in said pipe of changing degrees .of negative pressures over the range of speeds of said engine, a control member displaceable from an initial position of rest in one direction under the influence of negative fluid pressures thereon, means exerting a substantially uniform pressure on said control member tending to return the same to its said intial position upon said displacement thereof, means exposing one face of said control member simultaneously to said static and dynamic vacua in said intake pipe to effect said operated by said displacement/of said control member to reduce the rate of fuel delivery by said fuel-supplying means as the total or combined negative pressures of'said vacua increase in negative value.

10. The combination with a fuel injection internal combustion engine having an air suction intake pipe and liquid fuel-supplying means, of speed control means for said engine comprising separate means in said intake pipe cooperating with the engine piston to create a static and a dynamic vacuum in said pipe of changing degrees of negative pressures over the range of speeds of said engine, a control member displaceable from an initial position of rest in one direction under the influence of negative fluid pressures thereon,

- means exerting a substantially uniform pressure 76 on said control member tending to return the same to its said initial position upon said displacement thereof, means operative to so expose one face of said control member to said static and dynamic vacua in said intake pipe as to vary the proportional effect on said control member of one of said vacua relative to the other in displacing said control member, and means operated by displacement of said control member under the influence of said vacua to reduce the rate of fuel delivery of said'fuel-supplying means in accord ance with the extent of displacement of said control member. I

11. The combination with a fuel injection internal combustion engine having an air suction intake pipe and liquid fuel-supplying means, of

speed control means for said engine comprising means exerting a substantially uniform pressure on said control member tending to return the same to its said initial position upon said displacement thereof, means exposing one face of said control member either to said static vacuum or said dynamic vacuum or simultaneously to both said vacua to effect said displacement of said control member, and means operated by said displacement and return movement of said control member toadjustably reduce and increase and thereby control the rate of fuel delivery of said fuel-supplying means.

12. The combination with a fuel injection in ternal combustion engine having an air suction intake pipe and liquid fuel-supplying means, of speed control means for said engine comprising separate means in said intake pipe cooperating with the engine piston to create a static and a dynamic vacuum in said pipe of changing degrees of negative pressures over the range of speeds of said engine, a control member displaceable from an initial position of rest in one direction under the influence of negative fluid pressures thereon, means exerting a substantially uniform pressure on said control member tending to return the same to its said initial-position upon said displacement thereof, means operative at .idling speeds of said engine to expose one face of said control member to said static vacuum to eflect displacement of said control member in said one direction without exposing said member to said dynamic vacuum, operative at a higher speed of said engine to expose said one face of said control member tosaid dynamic vacuum to effect displacement of said control member in said one direction without exposing said member to said static vacuum and operative at an intermediate speed of said engine to expose said one face of said control member simultaneously to said static and dynamic vacua to eifect displacement of said control member under the influence of both said vacua, and means operated by displacement of said control member to reduce the rate of fuel delivery of said fuel-supplying means in accord- ;ance with the extent of displacement of said control member.

13. The combination with a fuel injection internal combustion engine having an air suction intake pipe and a fuel injection pump driven by said engine, of speed control means for said engine comprising a constriction in said intake pipe operating on reciprocation of the engine piston to produce a dynamic vacuum in said intake pipe of varying degrees of negative pressures over the range of speeds of said engine, a throttle valve in said intake pipe operating on reciprocation of the engine piston to produce a static vacuum in said pipe of varying degrees of negative pressure over the range of speeds of said engine, a control member displaceable from an initial position of rest in one direction under the influence of negative fluid-pressures thereon, means exerting a substantially uniform pressure on said control member tending to return the same to its said initial position-upon said displacement thereof, means exposing one face of said control member to said static and dynamic vacua in said intake pipe to effect said displacement of said control member to varying extents in accordance with said changing degrees of negative pressures of said vacua, and means operated by said displacement of said control member to reduce the rate of fuel delivery of said pump in accordance with the extent of displacement of said control member consequent upon changes in the total of combined negative pressures of said vacua.

14a A multi-cylinder internal combustion engine, including in combination an induction passage, a venturi constituting part of the induction passage, a throttle valve controlling the air inlet of the induction passage, a metering pump driven by the engine for introducing liquid fuel separately into the air charge for each cylinder to form a combustible mixture, a control member for varying the quantity of ,fuel delivered by the metering pump, a member subject to and movable in accordance with variations in the pressure at the throat of the venturi, and means whereby movement of the said member effects movement of the metering pump control member to reduce the quantity of fuel delivered when the pressure at the Venturi throat is reduced and .to increase the quantity of fuel delivered when the pressure at 

